Connector



June 13, 1967 J. F. LANCASTER CONNECTOR Filed July 12, 1965 INVENTOR JESSE F. LANCASTER Jim, M, M,

ATTORNEYS United States Patent Ofi ice 3,325,767 Patented June 13, 1967 3,325,767 CGNNECTOR Jesse F. Lancaster, Great Falls, Va., assignor to Cooke Engineering Company, Alexandria, Va., a corporation of Delaware Filed July 12, 1965, Ser. No. 471,105 12 Claims. (Cl. 339-89) This invention relates to electrical connectors, and in particular to separable connectors for coaxial or shielded wire transmission lines having a central conductor and an outer conductor. The latter is generally of braided wire forming a tube surrounding the central conductor, from which it is normally separated by a flexible tube of insulating material that maintains the central and outer conductors concentric.

Connectors for coaxial transmission lines provide means by which the line is terminated and the inner and outer conductors may be permanently or separably connected to a fitting or receptor that transmits the waver from a source to a receiver of energy or to another coaxial line for further transmission.

It is important that such connectors be constructed as to minimize losses or irregularities in the transmission of energy from the source to the receiver. In the case of separable connectors especially, they must also be constructed so that their electrical performance characteristics are not affected by wear and the like resulting from repeated connect and disconnect operations, or by strain resulting from the handling of the coaxial transmission lines, as when equipment to which they are connected is moved about.

Separable connectors should be so constructed so to be easily and quickly connected and disconnected, and at the same time the electrical performance characteristics should remain uniform after repeated connections and separations.

The prior 'art is exemplified by the US. Patents 1,667,485 to MacDonald; 2,449,073 to Johannesen; 2,877,437 to Flanagan, IL; and 2,958,845 to Dupree et al.

It is accordingly a principal object of the present invention to provide a novel separable connector for the terminal end of a coaxial transmission line which is rugged, easily separable from the fitting or receptor to which it is connected, and which minimizes losses or irregularities in the transmission of energy from the transmission line to the fitting, or vice versa.

Another important object is the provision of a novel connector for a coaxial transmission line wherein both the inner and outer Walls of a tubular fitting are frictionally engaged by the connector to provide a dual path for the flow of electrical energy between the connector and the tubular fitting or receptor.

It is still another important object of the invention to provide a novel separable connector for the terminal end of a coaxial cable to a fitting wherein the connector may be slipped onto or removed from a fitting and has a tight frictional engagement with the fitting when secured theret0.

Another object of the invention is to provide a novel separable connector between a coaxial cable and a fitting wherein there is a frictional engagement between the connector and the fitting and wherein compact clamping means are provided to prevent disengagement of the connector from the fitting.

Other objects will become apparent as the description proceeds in connection with the accompanying drawings, wherein:

FIGURE 1 is a view in side elevation, partly in vertical section along the centerline of a self-normaling jack having one embodiment of the connector secured to the lower of its fittings and another embodiment of the connector in alignment with, but not connected, to the upper of its fitttings.

FIGURE 2 is a view in end elevation of the connector in alignment with the upper fitting, as viewed from its left end in FIGURE 1.

Referring to FIGURE 1 a portion of a self-normaling jack is indicated generally by the reference numeral 5. It has two parallel tubular shields 6 and 7 which extend through and are rigidly secured to a common bar 8. Within shield 7 is a conductor 9 which is mounted centrally therein by an insulator 10 and within shield 6 is a similar central conductor 11 mounted by a similar insulator, not shown. A transverse conductor 12, in its normal position, connects the central conductors 9 and 11. Thus when coaxial cables indicated generally at 15 and 16 at the right end of FIGURE 1 have connectors 17 and 18 attached thereto and the connectors are secured to the right ends of the shields 6 and 7, the cable 15 is connected to the cable 16 via the self-normaling jack 5.

The jack 5, which may be also described as a normalthru coaxial switching and line terminating jack, does not, per se, form any part of the invention, but is shown only to illustrate an environment wherein connectors em bodying the instant invention are particularly useful, its structure in all material respects being fully shown in United States Patent No. 3,036,169, issued May 22, 1962 to Kienlen and Hayward for Shielded Electrical Switch.

Customarily, a number of jacks such as the jack 5 are mounted on a vertical panel called a jackfield, being secured thereto as by screws threaded into the common bar 8. The left ends of the tubular shields protrude through the panel, not shown, and are thus accessible for the insertion of patchcord plugs or dummy plugs. Such a plug on a patchcord will, when inserted into the lower shield 7, connect the inner conductor of a coaxial cable patchcord to the conduct-or 9 of the jack and the outer conductor to the shield 7, thus connecting the patchcord to coaxial cable 16 through the connector 18. Just before establishing connection with the central conductor 9 it will disengage the transverse conduct-or 12 from the connector 9 in the following manner.

The transverse conductor 12 is loosely mounted adjacent its ends in holes passing through a pair of plates 19 and 20 of insulating material which are journaled for rotation on a fixed pin 21. The plates 19 and 20 are urged toward the central conductors 9 and 11 by springs 25 and 26, thus presssing the transverse conductor 12 against both central conductors 9 and 11. When a pathcord plug is inserted into the left end of the lower shield 7 it will engage the inclined face of the plate 19 and move it away from conductor 9 and before its central connector engages the central conductor 9 it will have moved the transverse conductor 12 out of engagement with conductor 9. This will not effect the engagement of the other end of the transverse conductor 12 with the upper central conductor 11 because of the loose mounting of the conductor 12 in the holes in the plates 19 and 20. Axial movement of the conductor 12 is limited by a tube 27 of insulating material affixed around it. Insertion of a second patchcord plug into the left end of upper shield 6 will result in a similar disengagement of transverse conductor 12 from central conductor 11. Removal of the patchcord plugs Will re-esta'blish connection of coaxial cables 15 and 16. This connection can be broken "by the insertion of a dummy plug into either shield 6 or -7.

Turning now to a description of the invention as embodied in the connectors 17 and 18, the lower connector 18 will be described first, as it includes a locking device not used in the upper connect-or 17, and the same reference numbers will be used for both connectors where the parts are similar.

A metallic end bushing 28 includes a central bore 29 through which extends the inner conductor 30 and its surrounding insulation 31 of the coaxial cable 16. At its right end the bushing has a protruding thin walled nipple 32 over which is slipped the braided wire outer conductor 33 and its covering insulation 37. A suitable clamp 38 securely affixes the braided outer conductor and its insulaangularly spaced small depressions 43 which may be formed by drilling shallow blind holes in the outer wall.

Only one of the four depressions is shown. After insertionof the insulator 40 into the bore in bushing 28 a swaging tool is used to deform the bottom walls of the depressions 43 so that they will project slightly into the outer surface of the insulator, thus securely locking it in place.

A cylindrical front tip insulator 45 has a force fit within a metallic hollow cylindrical inner sleeve conductor 46, being seated against a shoulder 47 thereon. The insulator 45 is substantially the same length as the inner sleeve conductor46 and has an inwardly directed annular wall 48 which surrounds the central pin 41 substantially mid-point of its length. The central pin 41 terminates at its left end portion in a reduced diameter section 49 that has a slight taper for engagement with a mating tapered bore in the right hand end of the conductor 9. The insulator within the shield 7 has a reduced diameter portion that slips into a mating bore within the front tip insulator 45 when the connector 18 is connected to the shield 7 of the jack 5.

The right end of the hollow cylindrical inner sleeve conductor 46 abuts against the left end of the end bushing 28, which is threaded externally at 51 for mating engagement with internal threads on a hollow cylindrical outer sleeve conductor 42. In the case of the upper connector 17, the outer surface of outer sleeve conductor 52 may be knurled. On its inner surface the outer sleeve conductor 52 has an inwardly projecting annular rib 53 which engages an annular peripheral shoulder 54 in the inner sleeve conductor 46 so that it clamps the conductor 46 against the end of bushing 28 when the outer sleeve conductor is threaded onto the threads 51 of the bushing.

Inner sleeve conductor 46 is slightly reduced in outer diameter for substantially its left half portion 55, and terminates at its left end with a rounded projecting external flange 56. The reduced diameter portion 55 of conductor 46 has six axially extending equiangularly spaced radial slots 57 therethrough, thus forming six legs 59, as shown in FIGURE 2. Referring to the upper connector 17 of FIGURE 1, which has not been slipped onto the jack shield 6, the legs 59 are shown to fiare slightly outwardly so that their outer diameter at their rounded projecting end flanges 56 is slightly larger than the inner diameter of the tubular shield 6. Thus the legs 59 are compressed inwardly as they are inserted into the shield 6, to the position shown in the lower connector 18 of FIGURE 1 and they then press resiliently outwardly against the inner wall of the shield, establishing a good electrical contact between the shield and the inner sleeve conductor 46, which in turn makes contact at'its right end with the end of bushing 28 and at its shoulder 54 with the outer sleeve conductor 52.

For substantially the left half of its length the inner diameter of the outer sleeve conductor 52 is just a little larger in diameter than the fitting to which the connector is to be attached, such as the shield 6 or 7 of the jack 5. Adjacent its left end the inner surface of conductor 52 has an inwardly projecting annular ridge 60. That left half portion of conductor 52 that is to he slipped over a fitting has four axially extending equiangularly spaced radial slots 61 therethrough, thus dividing this portion of the conductor into four legs 62 as shown in FIGURE 2. The inner diameter of the ridge 60 is smaller than that of the outerdiameter of the fitting such as shield 6 or 7, and is of such diameter that the ridge 60 will snugly engage in a peripheral or ring groove in the fitting, such as a groove 63 best shown in the upper shield 6 of FIGURE 1. Such groove in the fitting is not necessary to the establishment of a good electrical contact between the legs 62 of the outer sleeve conductor 52 and the fitting, but the groove does provide a snap on retention device to prevent the inadvertent separation of the connector from the fitting because of vibration or the like. The groove 63 is located for engagement by the ridge 60 when the connector 17 or 18 is fully engaged with the fitting.

The connectors 17 or 18 may be used with standard BNC female connectors by adding the ring groove 63 to the female connector. The diametrically opposite bayonet projections on the BNC connector could be in the same or a different plane than the ring groove 63, but in any event the connectors 17 and 18 of the instant invention will slip over the projections merely by aligning the projections with a pair of oppositely disposed slots 61 in the. outer sleeve conductor 52.

The invention as described so far is applicable to either connector 17 or connector 18 of FIGURE 1, both of which provide dual coaxial paths for the passage of electrical energy from the tubular shields of a jack to the end bushing 28. This provides greater conductor density which is particularly important where the connectors are small because of space limitations. In view of the secure mounting of the cable terminus on the bushing 28 the connector may be inserted or disconnected from the fitting or jack by pushing or pulling on the coaxial cable without damaging the cable or connector. It provides a means of terminating the larger video coaxial cables without using an adaptor from the UHF to the BNC series of connectors.

The lower connector 18 in FIGURE 1 has an additional feature for locking the connector onto the shield 7. In this connector the outer surface of the outer sleeve conductor 52 to the right of its four legs 62 is threaded at 58 to receive a locking barrel 65 having internal threads 64. The barrel 65 may have a knurled outer surface to facilitate turning it by hand.

Barrel 65 is free to rotate so as to move to the right or to the left when the threads on the sleeve conductor 52 depending upon the direction it is turned. At its left portion it has an inwardly projecting annular ridge 6 9 having an inclined camming surface 70 that faces a similarly inclingl camming surface 71 on the outer ends of the legs 62 of theouter sleeve conductor 52. With the annular ridge on the legs 62 seated in the ring groove 63 and the locking barrel turned so that its camming surface 70 is seated against the camming surface 71 on the outer sleeve conductor 52, it is impossible to remove the conductor 18 from the fitting (shield 7) to which it is connected since it is effectively locked thereon by the locking barrel 65. Because of the camming action of the similarly inclined surfaces 70 and 71 the pressure of the ridge 60 against the surface of the ring groove 63 is increased over and above that which is provided by the resilience of the legs 62 alone, and the efficiency of the electrical contact is accordingly increased.

To the right of the incline 70 on the ridge 69, as viewed in FIGURE 1, the inner bore diameter of the locking barrel 65 is sufficiently large to enable the legs 62 on the outer sleeve conductor 52 to spring outwardly to disengage their ridge-60 from the ring groove 63 when the locking barrel 65 is rotated so as to move its camming surface 70 to the left and away from alignment with the camming surface 71 on the legs 62. Thus the barrel 65 need be rotated only a few turns from its locking position to enable the connector to be disconnected from the fitting to which it is attached. It has a loose enough fit on the threads of the outer sleeve conductor so that it may be rotated with a single finger either to engage or disengage the camming surfaces 70 and 71.

Thus both connectors 17 and 18 may be quickly attached to or disconnected from a fitting by moving them axially. This is particularly advantageous where a number of fittings are crowded close together, for example on the back of a switchboard or a jackfield. Where UHF or BNC connectors are used in such locations there must be suflicient space between adjoining fittings to permit gripping the connectors by a thumb and forefinger to turn them. A closer spacing of the fittings is permissible with the connectors of the instant invention since the barrel 65 performs only a locking function and thereby requires only a minimum turning tongue, essentially only that required to overcome the friction at the threads. As a result, contact of but the tips of the thumb and/or forefinger is sufiicient to provide the slight tongue required.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive with the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to Patent is:

1. A connector for terminating a coaxial transmission line and connecting it to a tubular coaxial fitting or receptor, comprising:

(a) an end bushing for connection with the outer conductor of a coaxial cable and having a central passageway,

(b) a connecting pin in said passageway, insulated from said bushing, and adapted at its opposite ends for connection to the central conductor of a coaxial cable and to the central conductor of a coxial receptor,

(c) a hollow cylindrical inner sleeve conductor surrounding said connecting pin, connected to said end bushing and resiliently radially contractible at one end and thereby adapted to engage and establish electrical contact with the inner surface of a conductive tubular fitting or receptor,

(d) and a hollow cylindrical outer sleeve conductor surrounding said inner sleeve conductor, connected to said end bushing and resiliently radially expansible at one end and thereby adapted to engage and establish electrical contact with the outer surface of the same conductive tubular fitting or receptor.

2. The connector described in claim 1, wherein said hollow cylindrical outer sleeve conductor is internally threaded at its other end and said end bushing is externally threaded for mating threaded engagement therewith (a) and said inner and outer sleeve conductors having opposing engaging annular surfaces whereby said inner sleeve conductor is clamped to said end bushing by said outer sleeve conductor.

3. The connector described in claim 1, wherein the portion of said hollow cylindrical inner sleeve conductor at said one end remote from said bushing has at least one axially elongated radial slot therethrough whereby that portion is resiliently compressible to reduce its outer diameter which in its uncompressed condition is larger in diameter than the inner diameter of a mating tubular fitting or receptor.

4. The connector described in claim 1, wherein the portion of said hollow cylindrical inner sleeve conductor remote from said bushing has at least two axially elonbe secured by Letters 6 gated equiangularly spaced slots therethrough forming equiangularly spaced legs,

(a) said legs being bent outwardly so that at their free ends said conductor is larger in diameter than the inner diameter of a mating tube or receptor.

5. The connector described in claim 1, wherein the portion of said hollow cylindrical outer sleeve conductor remote from said end bushing has at least one axially elongated radial slot thcrethrough whereby that portion is radially expandible to increase its inner diameter, which in its unexpanded condition is smaller in diameter than the outer diameter of a mating tubular fitting or receptor.

6. The connector described in claim 1, wherein the portion of said hollow cylindrical outer sleeve conductor remote from said end bushing has at least two elongated equiangularly spaced axially elongated radial slots therethrough, forming equiangularly spaced legs, whereby that portion is radially expandible,

(a) each said leg adjacent its free end having an inwardly projecting annular ridge for engagement in an annular ring groove on the outer surface of a mating fitting or receptor,

(b) the inner diameter of said ridge being smaller than the outer diameter of a mating tubular fitting or receptor.

7. In the connector described in claim 6, means for locking said annular ridge to prevent its disengagement from the ring groove on a mating fitting.

8. In the connector described in claim 6, means for locking said annular ridge to prevent its disengagement from the ring groove on a mating fitting, comprising a cylindrical barrel movably mounted upon said cylindrical outer sleeve conductor and having a portion engageable in one position with the outer surface of said legs adjacent their free ends. 7

9. The connector described in claim 8 wherein,

(a) said barrel is loosely threaded upon the unslotted portion of said outer sleeve conductor,

(b) the inner wall of said barrel having a first annular cam surface,

(c) and the outer end portions of said legs on said outer sleeve conductor having a second cam surface engageable by said first cam surface in one axial position of said barrel.

10. In combination;

(a) a metallic tubular receptor having a central conductor,

(b) a connector for terminating a coaxial transmission line and connecting it to said receptor comprising an end bushing for connection with the outer conductor of a coaxial cable and having a central passageway,

(c) a connecting pin in said passageway, insulated from said bushing, and adapted at its opposite ends for connection to the central conductor of a coaxial cable and to the central conductor of said receptor,

(d) a tubular inner sleeve conductor surrounding said connecting pin, connected to said end bushing and adapted to engage the inner surface of said tubular receptor,

(e) a tubular outer sleeve conductor surrounding said inner sleeve conductor, connected to said end bushing an adapted to engage the outer surface of said tubular receptor,

(f) the outer dimension of said tubular inner sleeve conductor being slightly greater than the inner dimension of said tubular receptor when not connected thereto,

(g) the inner dimension of said tubular outer sleeve conductor being slightly smaller than the outer dimension of said tubular receptor when not connected thereto,

(h) and both said inner sleeve connector and said outer sleeve connector each being provided with at least one longitudinally extending slot therethrough at the end portions thereof remote from said end bushing,

(i) whereby the slotted portions of said inner sleeve connector and said outer sleeve connector may be resiliently deformed inwardly and outwardly respectively when in mating engagement with said tubular receptor.

11. The combination described in claim 10,

(a) wherein the end portion of one of said sleeve conductors is provided with a projection facing the adjoining surface of said tubular receptor,

(b) and the surface of said tubular receptor facing said projection is provided with a depression for engagement by said projection,

() whereby said projection and depression provide a resilient lock to prevent disconnection of said receptor and said connector by vibration or the like.

12. An electrical connector comprising:

(a) a tubular conductor having external threads on one end portion and a series of elongated equiangularly spaced radial slots therethrough for the remainder of its length forming a series of resilient radially expansible and contractible legs,

(b) means forming an outer peripheral camming surface at the outer end portions of said legs remote from said external threads,

(c) a locking barrel having internal threads for a substantial portion of its length adjacent one end thereof and threaded upon said tubular conductor external threads,

(d) said barrel having an unthreaded portion surrounding in radially spaced relation the outer portions of said legs and having adjacent it its end remote from its internal threads an internally facing camming surface for mating engagement with said camming surface at the outer end portions of said legs to preclude radial outward movement of said legs when said barrel is fully threaded onto said tubular conductor and said camming surfaces are there-by fully engaged,

(e) said locking barrel having an enlarged inner diameter portion between its internal threads and its internally facing camming surface, said enlarged inner diameter portions surrounding said legs and permitting expansion of said legs when said camming surfaces are disengaged,

(f) said legs on said tubular conductor having an inwardly projecting annular ridge adjacent their outer ends of a radial depth no greater than the radial spacing between said barrel enlarged diameter portion and the outer portion of said legs,

whereby the ridges on said legs may snap into an external ring groove on a tubular fitting and engagement of said camming surfaces on said legs and said =barrel prevents removal of said ridges from such a ring groove thus locking the connector to the fitting and disengagement of said camming surfaces permits radial expansion of said legs to disengage from which such a ring groove while said legs are surrounded by said barrel upon axial movement of said connector relative to such a tubular fitting.

References Cited UNITED STATES PATENTS 2,286,952 6/1942 Cannon et al. 339-89 X 2,983,893 5/1961 Jackson 33991 3,124,406 3/1964 Cook 339177 X 3,176,259 3/1965 Macnamara 339-9l MARVIN A. CHAMPION, Primary Examiner.

W. DONALD MILLER, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,325, 767 June 13, 1967 Jesse F. Lancaster It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 1, line 20, for "waver" read waves line 33, for "50", second occurrence, read as--; column 2, line 49, for "pathcord" read patchcord column 3, line 42, for "42" read 52 column 8, line 24, strike out "which".

Signed and sealed this 26th day of December 1967 (SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, J r.

Commissioner of Patents Attesting Officer 

1. A CONNECTOR FOR TERMINATING A COAXIAL TRANSMISSION LINE AND CONNECTING IT TO A TUBULAR COAXIAL FITTING OR RECEPTOR, COMPRISING: (A) AN END BUSHING FOR CONNECTION WITH THE OUTER CONDUCTOR OF A COAXIAL CABLE AND HAVING A CENTRAL PASSAGEWAY, (B) A CONNECTING PIN IN SAID PASSAGEWAY, INSULATED FROM SAID BUSHING, AND ADAPTED AT ITS OPPOSITE ENDS FOR CONNECTION TO THE CENTRAL CONDUCTOR OF A COAXIAL CABLE AND TO THE CENTRAL CONDUCTOR OF A COAXIAL RECEPTOR, (C) A HOLLOW CYLINDRICAL INNER SLEEVE CONDUCTOR SURROUNDING SAID CONNECTING PIN, CONNECTED TO SAID END BUSHING AND RESILIENTLY RADIALLY CONTRACTIBLE AT ONE 